Curated with aloha by
Ted Mooney, P.E. RET
The authoritative public forum
for Metal Finishing 1989-2025
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Blue Color Powder on Silver Plated Parts
Q. We are observing "blueish color" buildup on silver plated surface with under plated nickel (silver plate over nickel underplate) on copper-based substrates. We have seen tarnish with yellow or brown colors but never seen a "bluish discoloration or layer build up. The silver-plating line is based on silver cyanide. The plating process includes pre cleaning, acid etching, nickel strike, nickel underplate, and finally silver plate. We will have a hot DI rinse with an anti-tarnish chemical to prevent immediate tarnish, while we assemble parts to it and ship to Customer.
I would request some help and guidance on this issue.
1) Is the bluish color or layer we found on the silver-plated surface is "Tarnish".
2) If Tarnish, why this is showing "blueish color" other than black or brown
3) Is the bluish color on the surface is due to improper or insufficient rinse?
4) Does the cyanide-based silver plating can cause bluish color on silver plated surface.
Quality Manager - Chicago, Illinois
April 22, 2025
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